Can recent DESI BAO measurements accommodate a negative cosmological constant? This study investigates whether the latest DESI BAO data can support a negative cosmological constant (CC) in the context of the $ w_{0}w_{a}CDM+CC $ model. Using recent DESI BAO measurements combined with Planck CMB and Pantheon Plus datasets, the authors perform a Markov Chain Monte Carlo (MCMC) analysis. The results show that the best-fit energy density of the CC is $ \Omega_{\Lambda} \sim -0.3 $, slightly preferred by the data with $ \Delta\chi^{2} \sim -0.8 $, while $ \Omega_{\Lambda} = 0 $ is also $ 1\sigma $ consistent. The negative CC slightly improves the fit to DESI data, although a small positive CC $ \Omega_{\Lambda} \lesssim 0.6 $ is also $ 1\sigma $ consistent. The study also finds that the $ w_{0}w_{a} $ component of DE is not still preferred by $ \gtrsim 2\sigma $ C.L., but the inclusion of a negative CC makes $ w_{0} $ and $ w_{a} $ closer to $ w_{0} = -1 $ and $ w_{a} = 0 $. The results suggest that a moderate negative CC $ \Omega_{\Lambda} \sim -0.3 $ is preferred by the Planck18+DESI+Pantheon Plus dataset, as it suggests $ w_{0,eff} \sim -0.8 $ and $ w_{a,eff} \sim -0.7 $. The study also finds that a negative CC could slightly suppress $ D_{H}(z)/r_{d} $ and $ D_{M}(z)/r_{d} $ at low redshift, leading to a slightly better fit to DESI data at effective redshifts $ z_{eff} = 0.51 $ and $ z_{eff} = 0.71 $. The results indicate that a negative CC might be an observable imprint of AdS vacuum, and further surveys could help determine its existence. The study also discusses the implications of a negative CC in the context of dark energy and the Hubble tension.Can recent DESI BAO measurements accommodate a negative cosmological constant? This study investigates whether the latest DESI BAO data can support a negative cosmological constant (CC) in the context of the $ w_{0}w_{a}CDM+CC $ model. Using recent DESI BAO measurements combined with Planck CMB and Pantheon Plus datasets, the authors perform a Markov Chain Monte Carlo (MCMC) analysis. The results show that the best-fit energy density of the CC is $ \Omega_{\Lambda} \sim -0.3 $, slightly preferred by the data with $ \Delta\chi^{2} \sim -0.8 $, while $ \Omega_{\Lambda} = 0 $ is also $ 1\sigma $ consistent. The negative CC slightly improves the fit to DESI data, although a small positive CC $ \Omega_{\Lambda} \lesssim 0.6 $ is also $ 1\sigma $ consistent. The study also finds that the $ w_{0}w_{a} $ component of DE is not still preferred by $ \gtrsim 2\sigma $ C.L., but the inclusion of a negative CC makes $ w_{0} $ and $ w_{a} $ closer to $ w_{0} = -1 $ and $ w_{a} = 0 $. The results suggest that a moderate negative CC $ \Omega_{\Lambda} \sim -0.3 $ is preferred by the Planck18+DESI+Pantheon Plus dataset, as it suggests $ w_{0,eff} \sim -0.8 $ and $ w_{a,eff} \sim -0.7 $. The study also finds that a negative CC could slightly suppress $ D_{H}(z)/r_{d} $ and $ D_{M}(z)/r_{d} $ at low redshift, leading to a slightly better fit to DESI data at effective redshifts $ z_{eff} = 0.51 $ and $ z_{eff} = 0.71 $. The results indicate that a negative CC might be an observable imprint of AdS vacuum, and further surveys could help determine its existence. The study also discusses the implications of a negative CC in the context of dark energy and the Hubble tension.